One of the most useful and popular vehicles today is the pickup truck, both for commercial and hobby activities. As part of the acceptance of pickups, not only for general transportation, hauling, top-cover carrying of tools and camping supplies, and pulling trailers and the like, is the desire for versatility. Of primary importance is the ability to use the bed of the pickup as a platform for hauling heavy objects.
Since pickup trucks have a load-rated hauling level much greater than one or two humans can quickly load into the bed, it has become desirable to be able to quickly and efficiently lift heavy objects into the pickup. Examples of loads are farm supplies such as animal feed, seeds and fertilizers, and the like. Hay bales are a common product carried by pickup trucks.
A number of the patents are to hay bale lifting devices. Goodvin U.S. Pat. No. 4,084,708 discloses a hay bale lifter that pivots about the hitch and lifts the unit using an electric winch. Krein et al U.S. Pat. No. 4,090,624 discloses a complicated hydraulic mechanism for lifting hay bales using a `lost motion` means. Gilbert U.S. Pat. No. 4,128,179 is another bale loader using an electric winch. This patent also suggests that the device can be used as a crane for lifting other items.
Lynch U.S. Pat. No. 4,288,191 also uses an electric winch to life bales. Hostetler U.S. Pat. No. 4,594,041 lifts bales of hay onto a flat bed truck. Krinhop U.S. Pat. No. 5,662,449 is the most recent hay bale lifting device using a winch.
Several other patents disclose devices that do engage the trailer hitch, but not for lifting purposes. Schwarz et al U.S. Pat. No. 3,805,984 discloses a motorcycle carrier that is attached to a conventional trailer hitch. It does not disclose a hydraulic lifting system, nor is it inserted into the box portion of the hitch. Sechovec U.S. Pat. No. 4,971,509 describes a carrier for handicapped vehicles that utilizes the trailer hitch, tilting to provide access to the device. It does not actually lift the vehicle. Jordan et al U.S. Pat. No. 5,649,732 uses a ramp mounted in the trailer hitch, again without using a lifting capability.
Finally, Clapp U.S. Pat. No. 4,591,309, assigned to Champion Corporation, discloses a hydraulic real loader using two arms and refers back to my 1974 U.S. Pat. No. 3,820,673.
Clearly none of these patents disclose a simple device supported on the centerline hitch of a vehicle and using a hydraulic mechanism to lift loads without resort to complicated, expensive or elaborate mechanisms. None of the prior art provides a simple device for insertion into an existing trailer hitch by one person working alone, whereby the device is capable of easily lifting and loading up to at least 830 pounds or more without assistance. Particularly, no prior device exists for lifting large loads within a space not much larger than the area taken by the vehicle itself.
Accordingly, it is an object of the present invention to provide a lifting device for use with a pickup truck or other similar platform.
A further object of this invention is to provide a lifting device which does not unbalance the platform by placing weight or stress on one side over another side of the platform, thus requiring bracing and extra support when used with heavy loads.
Yet another object of this invention is to provide a lifting device that is easily attached to a vehicle, such as a pickup truck, by one individual of average strength, yet which device is capable of being stored on the vehicle or in a storage facility when not in use.
Other objects will appear hereinafter.